Tank for use in storing low-temperature liquefied gas

ABSTRACT

A tank for storing a low-temperature liquefied gas in which the internal pressure on a thin film inner vessel composed of a sidewall and a bottom wall and an open top is supported by an outer vessel having a rigid, fluidtight construction and inside of which a heat-insulating layer is installed. Deformation of the inner vessel caused by the change of temperature or liquid pressure is absorbed by a change of curvature of a curved shoulder of an upper end portion of the sidewall of the inner vessel and by a sliding movement of the inner vessel wall allowed by a curved or arcuate corner of the lower end portion of the sidewall of the inner vessel. The strength of the inner vessel is maintained and at the same time leakage of liquid is prevented by suspending the pipes leading into the inner vessel through a trunk mounted on the top structure of the outer vessel.

United States Patent [72] Inventor Katsuro Yamamoto Tokyo, Japan [21] Appl. No. 865,441 [22] Filed Oct. 10, 1969 [45] Patented July 27, 19' [73] Assignee Bridgestone Liquefied Gas Company Limited Tokyo, Japan [32] Priority Oct. 11, 1968 [33] Japan [31 43/73,765

[ 54] TANK FOR USE IN STORING LOW- TEMPERATURE LIQUEFIED GAS 9 Claims, 1 Drawing Fig. 52 us. c|..' .1

[51 Int. Cl 865d 7/22 [50] Field of Search 220/9 LG, 9

[56] References Cited UNITED STATES PATENTS 2,460,355 2/ 1949 Kornemann i. 220/9 LG UX 2,889.953 6/1959 Morrison Primary Examiner-Joseph R Leclair Assistant E.raminer.lames R Garrett Anorneys- Robert E. Burns and Emmanuel .l. Lobato ABSTRACT: A tank for storing a low-temperature liquefied gas in which the internal pressure on a thin film inner vessel composed of a sidewall and a bottom wall and an open top is supported by an outer vessel having a rigid, fluidtight construction and inside of which a heat-insulating layer is installed. Deformation of the inner vessel caused by the change of temperature or liquid pressure is absorbed by a change of curvature of a curved shoulder of an upper end portion of the sidewall of the inner vessel and by a sliding movement of the inner vessel wall allowed by a curved or arcuate corner of the lower end portion of the sidewall of the inner vessel. The strength of the inner vessel is maintained and at the same time leakage of liquid is prevented by suspending the pipes leading into the inner vessel through a trunk mounted on the top structure of the outer vessel.

' k wi/392% TANK ron use IN STORING Low-TEMPERATURE uourzrmn GAS The present invention relates generally to storage tanks and longitudinal section illustrating a tank, for use instoring low temperature liquefied gas-,as one practical embodiment of the more particularly to a tank for use in storing low-temperature plicated affects as the expansion and contraction due to thermal change and the expansion by liquid pressure or the deformation by liquid weight, the conventional tank of the above mentioned type always involvesa problem as to how the inner vessel of sucha tank should be supported in the outer vessel-of the tank. Thus for solution 'of this problem, a flexible inner vessel, of a tank, which is composed of a'corrugated sidewall and a bottom wall only and in which the upper end portion of the sidewall is supported in a movable way, have just begun to be studied.

1 A principal object of the present invention is to provide a tank for use instoring low-temperature liquefied? gas with sufficient strength-and a high degreeofsafety in spite of the simple construction thereof.

The tank for use in storing low-temperature liquefied gas according to the present invention comprises an outer vessel having a rigid fluidtight construction. A heat'insulating layer having a compression resistantproperty is provided inside this outer 'vessel, and a flexible inner vesseihaving a fluid impermeable construction composed of a sidewall and'a bottom wall is provided inside thisheat-insulating layeriso that the fluid pressure inside the inner vessel of the tank can be supported with the wall of the outer vessel through the wall of the inner vessel and-the heat-insulating layer. A curvedcorner is formed at the connecting portion of the sidewall with the bottom wall of the inner vessel. The 'upper end portion of the i sidewall of the innervessel is formed so as to be curved radially inwardly to fit up the endv part of the upper end portion to the inside of the peripheral portion of the top wall or top structure of the outer vessel.

Moreover, in accordance with the tank of the present invention, a space between the inner and theouter vesselis common with a gas space within the inner vessel through the, part of the heat-insulating layer inside the top wall of the outer vessel. All the pipes leading to the inside of theinner vessel are suspended through a trunk mounted on the top wall or top structure of the outer vessel. I

Thus, according to this construction, almost every complicated deformation produced by a change-of temperature and that of fluid pressure is allowed as the result of a balanced deformation as a whole of the flexibility of the innerves'sel and as the result of the partial movement of expansion and contraction at an inwardly curved portion, formed at the upper end portion of the inner vessel and at the portion of a curved corner. And thus damage and destruction of the inner-vessel is completely prevented. a

Since the space between the inner and the outer vessel is common with the gas space within the inner vessel through the heat-insulating layer inside the top wall or top structure of the outer vessel, internal pressure acting upon the inner vessel is moderated and the space between the inner and the outer ves sel is kept in a dry state.

Since the piping leading to the inside of the inner vessel is all suspended through the trunk mounted-on the top structure of the outer vessel the general unfavorable problem from the point of 'view of the strength of the inner vessel, requiring that the penetrating holes of the pipes etc. must be made in the thin wall of the flexible inner vessel is solved. And if there should be any damage to a part of the vessel wall by the penetration. of the pipes through the trunk, liquid in the inner vessel can be prevented from any leakagebccause the damaged part is kept present invention a Referring more particularly to the drawing, there is shown a foundation structure 1, on which an outer vessel 2 having a rigid fluidtight construction is mounted. The tank is composed of a bottom wall, 2', a sidewall 2" and a'top wall or top structure 2' which are all made ofsteel. A heat-insulating layer, 3'

0 resistant to compression, made of perlite concrete is provided inside the bottom wall 2' while side and top heat-insulating layers 3", 3"" which are resistant to compression are composed of rigid foamed polyurethane. The side and top insulating layers are disposed inside each of the sidewall 2" and the top wall 2". But perlite concrete may be also used as the heat-insulating layer 3" inside the sidewall 2".

On the other hand, a material such as a steel, which has a comparatively excellent anti-low-temperature property, is desirable for use as the bottom wall 2' and in the neighborhood c of the connecting portion of the sidewall 2 with the top wall 2"" of the outer vessel. For other wall portions of the outer vessel, ordinary steel or high-tensile steel is used.

on the inside ofthe heat-insulating'layers 3 3" inside the outer vessel 2, a flexible and, for instance, corrugated inner vessel 4 having a impermeable construction, made of stainless steel of 3 mm. in thickness is provided. This inner vessel 4 is composed of only a bottom wall 4' and a corrugated sidewall 4". A curvedcorner portion 421 is formed at the connecting portion of the bottom wall 4' with the sidewall 4".

At the upper end portion of this sidewall 4", a'radially inwardly curved shoulder portion 4b is formed, and its end part 4c is fixed on the inside of the peripheral portion or inner surface of the-top wall or top structure 2' of the outervessel. Of course, a heat-insulating layer can be interposed at this fixed part, but between the curved shoulder portion 4b and the top and side heat-insulating layers 3", 3", there is an empty space Sand deformation of the curved shoulder portion 4b is thereby allowed.

and each space 5, 6 between the outer vessel 2 and the inner vessel 4 is common with a gas space 7 within the inner vessel 4." And all the pipes or conduits's'uch as a liquid pipe 8 and a vapor pipe 8' leading to the inside of the inner vessel 4 are suspended through a trunk mounted on the top wall of the outer vessel, and are constituted so that the penetrating holes for the pipes may not be installed through the inner vessel 4 itself.

The tank according to the present invention works as follows; To begin with,'when low-temperature liquefied gas is charged into the inner vessel through the liquid pipe 8, gas within the inner vessel 4 is vented through the vapor pipe 8', and a gradual contraction of the inner vessel 4 is caused by the low temperature thereof. At this time the curved shoulder portion 4b extends almost to a straight line position with a decrease of the curvature thereof, and allows a sliding movement towards the downward or lower portion of the sidewall 4" together with a smooth partial movement toward the bottom wall 4' at the curved corner portion 4a.

When the liquid surface 9 of the liquefied gas within the inner vessel 4 rises or moves upwardly the inner vessel 4 is expanded by the internal pressure thereof, and the corrugations of the sidewall 4" are stretched. Any looseness and slack in the bottom wall 4' of the inner vessel is stretched by the liquid pressure. The sidewall 4" makes an upward movement through the curved corner portion 4a as it straightens. But the curved shoulder portion 41; can deform with an increase of the curvature of the vertical part thereof and absorb the deformation of the inner vessel 4 in cooperation with the partial movement executed at the lower curved corner portion 4a.

And even if waves are produced, for example by an earthquake etc., on the liquid surface within the inner vessel 4 and run high against the curved, upper shoulder portion 4b, the upper shoulder portion 4b is sufficiently strong to bear the forces due to its strength because of the hoop tension thereof. The spaces 5, 6 between the inner and outer vessels are common or in communication with the gas space 7 inside the inner vessel 4, and so the gas pressure of the sidewall 4" of the inner vessel 4 from the inside and outside thereof is properly balanced, and there is no trouble with the deformation of the curved upper shoulder portion 4b.

Moreover, in the tank of the present invention, all the pipes such as the liquid supply pipe 8 and the vapor pipe 8' etc. leading to the inside of the inner vessel 4 are suspended through a trunk mounted on the top wall or top structure of the outer vessel, and therefore if there should be any damage at a part of the vessel wall penetrated by the pipes 8, 8' through the trunk, the damaged part is above the liquid surface and is free of any liquid leakage.

in the above embodiment of the present invention, the heatinsulating layer 3" of the top portion is constituted so that at least a part thereof may have a gas draught property, but this can be a material without any gas draught property so that the space between the inner and outer vessels may be connected with the inside of the inner vessel through an opening formed at an appropriate place or connected through gas draught valves, not shown.

Thus the membrane tank, according to the present invention, for use in storing a low-temperature liquefied gas, a flexible inner vessel made ofa thin film is provided and the flexible inner vessel can be quite reasonably movably supported within a rigid outer vessel, and the low-temperature liquefied gas can be stored safely.

What I claim and desire to be secured by Letters Patent is:

1. A tank for storing low-temperature liquefied gas comprising, an outer rigid vessel having a bottom, a sidewall and a top structure, a heat-insulating layer in the interior of said outer vessel, :1 flexible, inner, fluid-containing vessel in the interior of said outer vessel interiorly of said heat-insulating layer, said inner vessel having a sidewall and a bottom made of a fluid-impervious material and an open top, said inner vessel having an annular deformable lower portion of arcuate configuration in radial cross section in the area ofjuncture of said sidewall and said bottom, the inner vessel having a deformable upper marginal portion defining the open top of said inner vessel and having an inwardly curved arcuate configuration in radial cross section, means securing a radially innermost edge portion of said upper marginal portion to the outer vessel top structure allowing said marginal portion to deform and straighten in radial cross section in response to temperature variations, said inner vessel and outer vessel defining an annular space between sidewalls thereof within which said heat-insulating layer is disposed and said space communicating with an upper space within the inner and outer vessels.

2. A tank for storing low-temperature liquefied gas according to claim I, in which the sidewall of said inner vessel is corrugated.

3. A tank for storing low-temperature liquefied gas according to claim 1, in which said heat-insulating layer comprises a compression-resistant material.

4. A tank for storing low-temperature liquefied gas accord ing to claim 1, in which said outer vessel includes a trunk in said top structure and conduits extending through said trunk into said inner vessel and into said upper space.

5. A tank for storing low-temperature liquefied gas according to claim 1, in which said outer vessel top structure and said upper marginal portion of said inner vessel defines a space between it said top structure as a continuation of said annular space and in communication with said upper space.

6. A tank for storing low-temperature liquefied gas according to claim 1, in which said inner vessel is made of thin steel.

7. A tank for storing low-temperature liquefied gas according to claim 6, in which said thin steel has a thickness in the order of 3 millimeters.

8. A tank for storing low-temperature liquefied gas according to claim 1, in which said upper marginal portion and said top structure define a space therebetween as a continuation of said annular space.

9. A tank for storing low-temperature liquefied gas accord ing to claim 8, in which said deformable lower portion cooperates with said deformable upper marginal portion and is responsive to deformation thereof to deform in cooperation with deformation of said marginal portion and allow flexing of said upper marginal portion so that it can assume a straightened configuration in radial cross section and said arcuate configuration in radial cross section. 

2. A tank for storing low-temperature liquefied gas according to claim 1, in which the sidewall of said inner vessel is corrugated.
 3. A tank for storing low-temperature liquefied gas according to claim 1, in which said heat-insulating layer comprises a compression-resistant material.
 4. A tank for storing low-temperature liquefied gas according to claim 1, in which said outer vessel includes a trunk in said top structure and conduits extending through said trunk into said inner vessel and into said upper space.
 5. A tank for storing low-temperature liquefied gas according to claim 1, in which said outer vessel top structure and said upper marginal portion of said inner vessel defines a space between it said top structure as a continuation of said annular space and in communication with said upper space.
 6. A tank for storing low-temperature liquefied gas according to claim 1, in which said inner vessel is made of thin steel.
 7. A tank for storing low-temperature liquefied gas according to claim 6, in which said thin steel has a thickness in the order of 3 millimeters.
 8. A tank for storing low-temperature liquefied gas according to claim 1, in which said upper marginal portion and said top structure define a space therebetween as a continuation of said annular space.
 9. A tank for storing low-temperature liquefied gas according to claim 8, in which said deformable lower portion cooperates with said deformable upper marginal portion and is responsive to deformation thereof to deform in cooperation with deformation of said marginal portion and allow flexing of said upper marginal portion so that it can assume a straightened configuration in radial cross section and said arcuate configuration in radial cross section. 